The long range objective of this research is to determine the processes which control metabolism of valine, isoleucine and leucine and the genetics related to the metabolism and regulation of these pathways. Bacteria have been used as an experimental model in the past studies and will continue to be used for part of the present studies. The knowledge gained from the studies with bacteria will be used to study the metabolism of the branch chain amino acids in man and eventually in patients with genetic disorders in the metabolism of these amino acids. In the current year we plan to complete some research on the purification and characterization of tiglyl-CoA-hydrase and possibly begin studies with normal human tissues.